Adapting to Extreme Weather

May 14, 2013

Last year’s heat and drought and this year’s late spring have added extra stress to lawns.

With buds finally starting to bloom on trees in the southern part of Minnesota and ice still stubbornly floating around on lakes in the north, it’s a good time to take stock of a strange year of weather and its effect on our lawns and vegetation.

To rehash the recent weather history that many of us may be trying to repress, we had an exceedingly wet and warm spring in 2012, followed by a summer and fall of extreme heat and certifiable drought. That took a toll on grass and trees—not to mention crops—all around the state.

And while we cut into the moisture deficit with a rather snowy winter, that winter only recently (mostly) released its grip on the landscape. And that landscape includes a lot of struggling vegetation.

A narrow window for recovery

According to Sam Bauer, turfgrass expert with University of Minnesota Extension, many people saw their grass wither and even die heading into the winter, especially if they didn’t provide extra irrigation in the fall.

A photo taken of a driving range in Hastings, MN after 10 inches of snow on May 2nd

To make matters worse, the painfully long winter has shortened the natural recovery period for grasses, when the root system develops enough to withstand the stresses of summer heat.

Normally, that window begins toward the end of April and lasts till early June. But this year we were still getting snow at the end of April en route to a monthly total of 17.6 inches—the snowiest month of the entire winter.

“Essentially, our window for recovery this spring is shortened, what with the cool temperatures we’ve had and the third snowiest April,” Bauer says. “Our recovery period is not much more than a month.”

So what to do? Bauer says it’s important to not be overly aggressive when raking this spring, and also to not mow your grass too short. Proper spring irrigation is also important.

And if you’re thinking of applying pre-emergent weed herbicides “for those lawns that have a history of crabgrass”, now is the time, Bauer says, as crabgrass will begin germinating when the soil is about 60 degrees.

Bauer also says now may be the time to explore planting lower maintenance, lower input grasses like fine fescues, depending on how you use your lawn and how much foot traffic it receives. (You can read more about fine fescues “In search of ‘greener’ grass”.) Fine fescues blend well with other grasses and tend to recover better from events like last year’s drought.

However, he cautions that if you do decide to inter-seed with another type of grass, you can’t apply the pre-emergent herbicide.

Assessing the health of plants

When it comes to vegetation aside from grass, “a lot of it is really looking around your yard and finding out how things did throughout the winter,” says Julie Weisenhorn, state director of the Extension Master Gardener Program.

There may be dieback, where the ends of plants perished in the winter. You should look for animal damage to thinner-bark plants like apple, cherry, and plum trees. But beware that it’s too late to prune fruit trees, and you should be careful not to prune oaks, either, Weisenhorn says.

On the positive side, you can be dividing plants like daylilies, hostas, and Siberian irises, and you can also start scheming what new things you may want to plant this year, bolstered by the thought the impending heat will make up for the pesky winter soon enough.

“It’s amazing—once the weather warms up—how fast the plants will sprout their leaves and get back on track,” she says.

But with all the speculation on how climate change may make Minnesota more amenable to plants that could previously only grow in zones to our south, Weisenhorn says you may want to wait a while before throwing caution to the prevailing wind.

“Part of the fun of gardening is taking a chance,” she says. “But if a plant is rated for Zone 5, people have to be aware that it may not survive a cold Minnesota winter.”